A DEADLY CONNECTION: How pollution is a hidden factor in suicide risk

City traffic is heavy, bringing much stress to the common commuter with its raucous noise, sweaty breeze, and also, the release of bellows upon bellows of blackened smoke into the atmosphere.

A study conducted by researchers at the University of California – Santa Barbara (UCSB) and Chinese University of Hong Kong, Shenzen (CUHK-Shenzen) suggests that higher air pollution levels may be linked to higher stress levels and suicidal ideations, as published in a journal on February 12 this year.

The paper, led by UCSB assistant professor Tamma Carleton and CUHK-Shenzen researcher Peng Zhang, discovered that efforts to reduce air pollution have prevented 45,970 suicide attempts in China. 

Studies on the possible therapeutic effects of a pollution-free environment are uncommon, yet nothing new. 

In 2015, researchers at Stanford University discovered that people who were exposed to nature showed decreased activity in the part of the brain linked to depression when compared to people otherwise exposed to urbanities.

A similar study, published by University of Chicago researchers in 2019, also probed into the psychiatric effects of environmental pollution. 

Both research showed that pollution, in its many forms, can affect the mental chemistry of the brain, and adversely affect our day-to-day lives.

Carleton, Zhang, and other co-researchers observed the “inversion” phenomenon to prove their hypothesis. This happens when warm air captures a layer of colder air and traps it in a certain area, which can concentrate particulate matter pollution to the ground level, leading to pollution that is not directly caused by human activity.

Particulate matter consists of tiny particles that cannot seen by the naked eye, hence, not only to the body, but to the environment. According to the United States Environmental Protection Agency, these particles pose the greatest risk to health.

Carleton said that among the challenges of their research was that “air pollution is correlated with a lot of things, [including economic activity, commuting patterns, and industrial output.”

The study, which was done by comparing statistics across 600 areas with their climate cycling inversions and regular weather, found that pollution, although not directly caused by human activity, influences human behavior, hence, untoward reactions such as self-harm, and anxiety, leading towards suicide.

Beyond reducing suicide rates, improving air quality can significantly benefit overall mental health. Exposure to high levels of pollution has been linked to cognitive, or thinking decline and increased stress levels, so decreasing pollution can enhance cognitive function and emotional stability. 

The numbers were linked with government policies within China. According to the study, China’s National Air Pollution Plan launched over a decade ago, was responsible for the prevention of thousands of suicide attempts from 2013-2017. 

However, pollution is not the only issue at hand. "About 10% of the overall decline over these past five years can be attributed to particulate pollution," Carleton said. 

"That's important, but it also leaves 90% unexplained by pollution," added Carleton.

On a global scale, reducing pollution can mitigate the impacts of climate change, leading to a more stable and hospitable environment. Adopting stringent pollution protocols for developing countries can help address health disparities and improve public health outcomes.

Understanding the link between pollution, however, and untoward suicide attempts enables communities, and even policymakers in government, to be aware of the possible impact of lowering dependence on pollutant substances, safeguarding communities that will otherwise be dependent, and affected, by these materials.

Carleton hopes that with the study, policymakers and governments can change how suicide is viewed and prevented in countries worldwide. 

“Public policy about air pollution—something you can't control, what's outside your window—is affecting the likelihood that you take your own life. And I think that puts a different lens on the solutions we should be thinking about,” Carleton said.

In the Philippines, where mental health remains a stigma and environmental protocols remain lip service to the government, several agencies have already gone go signal with minimizing pollution and praising “green spaces” to minimize mental health issues. 

In fact, the Department of Environment and Natural Resources (DENR) said in a statement that it is promoting the establishment of urban green spaces in the country. 

While the move was primarily to mitigate the effects of the increasing heat index, research from the Ateneo de Manila University in 2023 suggests that workers in areas with proximity to green spaces had lower stress levels, as well as higher resiliency indices. This translates into a much more efficient work ethic, especially with jobs with higher workloads.

Meanwhile, these policies can also stimulate economic benefits by reducing healthcare costs and increasing worker productivity due to better health. 

This proves that decreased pollution and environmental awareness are key to a mentally stable community that functions for the greater good of society. 

Pulling the strings on more stringent protocols on pollution is not just about clearing the air; it is about safeguarding mental health and preventing tragedies. 

Research from the UCSB and the CUHK-Shenzhen remain Sinocentric, which means that the results can otherwise be applied to developing countries, including the Philippines, where greater dependence on plastic and other pollutant materials leads to a higher pollution index.

The groundbreaking research has shown that improving air quality can reduce suicide attempts, but highlighting the impact of environmental policies on mental well-being is another matter to discuss. 

Closing the cap on pollution is an effort that can make or break society to a healthier future. The evidence is clear: cleaner air can save lives, not just by preventing physical illnesses, but by “making” mental stability and well-being. 

As nations worldwide take note of these findings, the hope is that comprehensive policies will be developed and enforced to reduce pollution, protect the environment, and enhance the quality of life for land.

And, of course, a less harsh city traffic.